Process of activating carbon



J. C. WOODRUFF.

PROCESS OF ACTIVATING CARBON. APPLICATION FILED MAY 8, 1919.

1,368,987.- Patented Feb. 15, 1921.

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UNHTEEB STATES PATENT @FFEQE JOHN c. woonnurr, or NEW Y RK, N. Y.

PROCESS ACTIVATING CARBON.

To all whom it concern: Be it known that I, JOHN C. WOODRUFF, a citizenof the United States, and residing at New York city, N. Y., haveinvented certain new and useful Improvements in Processes of ActivatingCarbon, of whichthe following is a specification. This invention relatesto the manufacture of absorbent carbon and has special reference to aprocess of rendering carbon, such as charcoal, highly active as anabsorbent. Heretofore, charcoal has been activated by means of steam invertical tube furnaces called Dorsite treaters. This type of furnaceconsists of a nichrome tube symmetrically set in a vertical position andsurrounded by a cylindrical combustion chamber heated .to about 1100 C.by gas burners. On the inside of the above mentioned nichrome tube,there is concentrically located a nichrome steam pipe having part of its'length perforated, and covered with n1- chrome wire cloth of ratherfine mesh which is smaller than the particles of the material treated.The gaseous products. of the reaction are drawn ofi through exhaustportsby means of a vacuum pump. Granular charcoal is introduced through ahopper valve feeding device at the top. The space surrounding the steamjet is. kept full of carbon and as a portion is discharged from thebottom of the tube, thus lowering the level of the material in the tube,the level is replenished through the feed valve at the top of thefurnace. Thus, a continuous gravity passage of the charcoal through thetube is maintained, unless interfered with by gas pockets, and thecharcoal is activated by the superheated steam admitted through thesteam 'et. 4

The big est quality of absorbent charcoal is obtained only by runningthe material at a very slow rate or by re-running it several timesthrough this type of furnace. This process re uires a large amount oftime and fuel. Di culty is experienced in feeding due to the formationof gas pockets which hold the charcoal from sliding after the materialis discharged from the bottom. The exhaust lines constantly give troubleby becoming plugged with charcoal.

Specification of Letters Patent. Patenjggdl Feb, 15, 1921, Applicationfiled May 8, 1919. Serial No. 295,62l;

come the disadvantages hereinbefore described in the prior processes.

Anotherfobject of this invention is to avoid the use of expensivenichrome tubes, which usually burn out and also have the troublesomesteam jets. Reference is to be had to the accompanymg drawmgs in whichFigure 1 isa view in elevation of the apparatus used in my process, partof the device, however, being shown 1n section.

2 is a section along the line 22 of 1g. This apparatus is similar to acement ln'ln in construction and operation and consists of a longslightly inclined cylinder (1), preferably of steel, and lined with arefrac tory substance (2), such as fire brick, and is mounted on rollers(3) so that it may be rotated. The high end of the cylinder has acharglng device (4) and an operating outlet (5) for the flue gases. Atthe lower end is a discharging devlce, shown in a diagrammatic way, bythe pipe (6). A fire brick box (7) at this. end provides for the burningof coal, coke, powdered coal or tar-oil and is so built that the hotflue gases pass throughthe revolving tube. Steam, air, CO or otheroxidizing agents are also admitted at this end.

Carbon is charged into the cylinder through the charging device (4) andas it passes through the cylinder it comes into contact with the hotflue gases and steam at a high temperature, and the material becomesreadily activated. It has been found that a temperatureof 700 to 1100 C.produces satisfactory results.

With this internally fired rotary furnace a high percenta e of yield mabe obtainedand the materia may be pro uced in very large quantities.lThe peculiar eficiency of the process depends primarily upon thecombined features of continuous agitation of the carbon while undergoingoxidation and the delivery 'of the oxidizing and heating gases directlyto 'the reaction chamber wherein they are mingled freely. with thecarbon while the required temperature is readily maintained. Byemploying the heating gases directly, the heat is conserved and theprocess rendered rapid and economical. The uniform and highly activeproduct ma be used for a variety of purposes to whlch it is adapted. i

The furnace described is more economical than the Dorsite apparatus fromthe standpoint of both installation and operation, and there are noexpensive nichrome tubes to be burned out nor troublesome jets withwhich to contend.

The present invention is not limited to the specific ,details set forthin the foregoing examples which should be construed as illustrative andnot by way of limitation, and in view of the numerous modificationswhich may be efiected therein without departing from the spirit andscope of this invention, it is desired that only such limitations beimposed as are indicated in the appended claims.

I claim as my invention:

1. A process of treating carbon by oxidation, which comprises,continuously agitating the carbon while conveying it through a reactionzone and subjectin the carbon while in said zone to the com ined actionof steam and hot combustion gases, the latter gases furnishing thenecessary heat to maintain the temperature at a point insuring rapidactivation of the carbon. 7

2. A process of treating carbon by oxidation, which comprises,continuously agitating the carbon while conveying it through a reactionzone and subjecting the carbon while in said zone to the combined actionof steam and hot combustion gases, the latter gases furnishing thenecessary heat to maintain atemperature of between 700 C. and 1100 C.

JOHN C. WOODRUFF.

